Federal regulators have opened an investigation into nearly 1.3 million Ford (F) F-150 trucks after consumers complained the vehicle unexpe✤ctedly downshifted while traveling at high speeds, causing it to rapidly slow down and increasing the risk of a crash. 

The National Highway Traffic Safety Administration said it has received 138 consumer complaints about F-150s from model years 2015 to 2017. In🦋 addition to the complaღints of unplanned downshifts, some customers said the drop to a lower gear caused the vehicle’s rear wheels to temporarily lock up, making it harder to control. No crashes or injuries have been reported.

A Ford spokesperson said the issue is related to the trucks' six-speed transmission, and the automaker is "working with NHTSA to support its investigation. "

The investigation comes after Ford recalled more than 240,000 Explorer models in February related to improperly secured seatbelts and earlier this month had to re-recall as many as 12,833 Bronco Sport and Maverick vehicles due to issues with repairs.

Shares of Ford rose more than 1% intraday Monday.